Experimental Investigation On Reaction Characteristics For Magnesium Residues As Sorbent

With the development of the magnesium industry in recent years, magnesium residues cause seriously environmental pollution. It has been an important problem how to apply the magnesium residues. If the magnesium residues could be used for desulfurization, the desulfurization cost would be decreased and the dust problem would be solved. This method will be of economic and environmental benefit.The prophase experimental results show that the calcium utilization rate for magnesium residues as desulphurization is low. Based on the forefather researches, the author uses hydration, steam activation and direct hydration to process magnesium residues. By means of X-ray Diffraction (XRD), Thermo Gravimetric Analysis (TGA) and Scanning Electronic Microscope (SEM), the effects of several main factors (particle diameter, temperature, etc), on desulfurization efficiency are discussed.The experimental results by XRD indicate that main composition in magnesium residues is Ca2SiO4, which is of 80.96% in mass. CaO and MgO are possessed of 5.04% and 9.02% separately. Fe2O3 and Al2O3 is 4.72%. It is CaO and Ca2SiO4 that participates in desulphurization, MgO in magnesium residues does not.The composition and temperature for the flue gas are stimulated in experiment. The calcium utilization rates are calculated by TGA. The results show that all of the activation methods may really improve the magnesium residues utilization by increasing specific surfaces and pore volumes. Compared with the magnesium residues cooled, the calcium utilization rate for the direct hydration is the highest (39.87%), for hydration activation the rate is 34.59% and for steam activation the rate is 32.68%.Surface areas and pore volumes for magnesium residues are determined by N-absorption before and after the desulphurization. The research results indicate that the direct hydration is the best method for improving desulphurization characteristics of magnesium residues. Compared with the magnesium residues cooled, the surface area and pore volume are separately increased by 1621.67% and 1422.22%. By SEM the surface roughness of the solid particles becomes bigger than the original. When the surface areas and pore volumes increase, the calcium utilization rate is improved. The results from SEM are in accordance with the ones by TGA.The research results from this thesis will provide an economic way for desulphurization and for a solution for magnesium residues pollution.